The unit also teaches military personnel to identify and avoid such deadly munitions, it provides technical assistance to local, state and federal authorities and serves as a round-the-clock crisis response force on base.

The deaths underscored the dangerous nature of Marine operations whether on training ranges at home or in combat, particularly for those whose job involves frequent contact with bombs and other high explosive munitions.

Seven Marines were killed and eight injured during live fire range training in Hawthorne, Nev., March 18 after improperly firing a mortar round, a command investigation found. The commanding officer of the East Coast battalion involved in the accident, a company commander and gunner were relieved of duty.

Investigators concluded that human error was to blame for the deaths and the Marines had not properly prepared for the mission, the 2nd Marine Division announced.

Mortar and artillery live fire exercises were scheduled for the Zulu/Whiskey areas of Camp Pendleton Wednesday, beginning at 6 a.m. and continuing all day and night, according to the Camp Pendleton noise advisory.

No explosives training was active, however, in the Zulu area at the time of the accident, said 1st Lt. Ryan Finnegan, a base spokesman. The high explosive munitions training in the Whiskey area is continuing as scheduled after the accident, he added.

The identities of the deceased Marines will be announced 24 hours after their families have been notified, Camp Pendleton Marines announced.

"We offer our heartfelt prayers and condolences to the families of the Marines lost today in this tragic accident. Our first priority is to provide the families with the support they need during this difficult time," said Brig. Gen. John W. Bullard, commanding general of Marine Corps Installations West and Marine Corps Base Camp Pendleton.

Relatives of any fallen service member who needs care and support may call the Tragedy Assistance Program for Survivors (TAPS) 24/7 resource and information hotline at 1-800-959-TAPS (8277).

TAPS has a memorandum of agreement with the U.S. Marine Corps to provide bereavement support to families of the dead.

"We are deeply saddened by the deaths of four Marines today during a range maintenance operation at Camp Pendleton. Our hearts and thoughts go out to the families left behind by the service members who died today. TAPS stands ready to assist families and friends who are grieving the death of a loved one serving in our armed forces," the organization said in a statement.